1. Field of the Invention
The invention relates to a gas laser having a discharge tube, through which the gas flows in an axial direction and to which high-frequency electrodes are fitted externally, and having a high-frequency generator.
2. Description of the Relevant Art
In such a gas laser, the high-frequency power is coupled via the electrodes capacitively into the gas to be excited. To date, for this purpose the power output stage was always connected to the electrodes via comparatively long conductors, for example coaxial conductors, since it was not considered to be possible to fit the power output stage in the vicinity of the discharge tube. In this connection, the disadvantage did, however, arise that in the first instance an impedance transformation had to be undertaken at the output of the power output stage, in order to obtain an adaptation to the impedance of the conductors, for example of the coaxial cable, which can amount, for example, to 50 ohms or 75 ohms. A further impedance adaptation or transformation was then necessary at the end of the conductor or of the coaxial cable, in order thus to couple the signal optimally out of the cable into the high-frequency electrodes, by means of which the gas is to be excited.
This two-fold impedance adaptation or transformation is very troublesome, and readily leads to non-ideal adaptation and power losses. Moreover, losses occur in the conductors, for example coaxial cables.